Composite powder for use in an anode of a lithium ion battery, method of preparing such a composite powder and method for analysing such a composite powder

Patent metadata

Field	Value
Publication number	US-10483529-B2
Application number	US-201515538706-A
Country	US
Kind code	B2
Filing date	Dec 11, 2015
Priority date	Dec 23, 2014
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Composite powder for use in an anode of a lithium ion battery, whereby the particles of the composite powder comprise silicon-based domains in a matrix, whereby the individual silicon-based domains are either free silicon-based domains that are not or not completely embedded in the matrix or are fully embedded silicon-based domains that are completely surrounded by the matrix, whereby the percentage of free silicon-based domains is lower than or equal to 4 weight % of the total amount of Si in metallic or oxidized state in the composite powder.

First claim

The invention claimed is:

1. A composite powder for use in an anode of a lithium ion battery, wherein particles of the composite powder comprise silicon-based domains in a matrix, and wherein the matrix comprises carbon or a precursor material that can be converted into carbon by thermal treatment, and wherein the individual silicon-based domains are either:
free silicon-based domains that are not or not completely embedded in the matrix, or
fully embedded silicon-based domains that are completely surrounded by the matrix,

wherein the percentage of free silicon-based domains is lower than or equal to 4 weight % of the total amount of Si in metallic or oxidized state in the composite powder, and
wherein the silicon-based domains have a weight based size distribution with a d 50 of 200 nm or less and a d 90 of 1000 nm or less, and wherein the composite powder also comprises graphite, wherein the graphite is not embedded in the matrix.

2. The composite powder according to claim 1 , wherein the percentage of free silicon-based domains is lower than 3 weight % of the total amount of Si in metallic or oxidised state in the composite powder.

3. The composite powder according to claim 1 , wherein the percentage of free silicon-based domains is the percentage as determined by placing a sample of the composite powder in an alkaline solution for a specified time, determining the volume of hydrogen that has evolved after the specified time, calculating the amount of silicon needed for evolving this amount of hydrogen based on a production of two moles of hydrogen for every mole of silicon reacted and dividing this by the total amount of Si in metallic or oxidised state present in the sample.

4. The composite powder according to claim 1 , wherein the powder contains less than 3 weight % of oxygen.

5. The composite powder according to claim 1 , wherein the powder contains between 2 weight % and 25 weight % of Si.

6. The composite powder according to claim 1 , wherein the matrix comprises pitch or thermally decomposed pitch.

7. The composite powder according to claim 1 , wherein the silicon-based domains are silicon-based particles.

8. The composite powder according to claim 1 , wherein the powder has an average particle diameter d 50 of between 1 and 20 microns.

9. The composite powder according to claim 1 , wherein at least 97% of the surface area of the silicon-based domains is covered by the matrix.

10. The composite powder according to claim 1 , wherein the silicon-based domains have a weight-based size distribution with a d 50 of 100 nm or less and a d 90 of 1000 nm or less.

11. The composite powder according to claim 1 , wherein a ratio between an average size of the composite powder and a d 50 of the silicon-based domains is 10 or more.

Assignees

• Umicore Nv
• Showa Denko Kk

Inventors

• Put Stijn
• Van Genechten Dirk
• Driesen Kris
• Hu Jin
• Strauven Yvan
• Muto Arihiro
• Ishii Nobuaki
• Takeuchi Masataka

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/0413

  Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title